Synthesis of new alicyclic polyimides by diels-alder polymerization

Four new alicyclic poly{arylene-9,10-di[4(methyloxy)phenyloxyl]-1,2,3,4,5,6,7,8-octahydroanthracene-2,3,6,7-tetracarboxdiimidels (APIs) were prepared at 80 degrees C in the presence of NaI in DMSO by the in situ Diels-Alder polymerization of I.,4-bis[4-(methyloxy)phenyloxy]-2,3,6,7tetrakis(bromomethyl)benzene (MPBB) with four arylene-bismaleimides (AMIs). The stereochernical isomerisms measured for the model compound DPAI and MDA-PI by HETCOR spectroscopy and H-1-NMR spectroscopy, respectively, revealed that DPAI and APIs presumably have only one trans-bis-endo-configuration. Inherent viscosities of APIs varied in the 0.20-0.41 dL/g range. Solubility tests revealed that in spite of the alicyclic units incorporated the APIs were only marginally soluble in polar organic solvents. In TGA in N-2 the APIs began to decompose at temperatures higher than 380 degrees C, revealing two-step pyrolysis behavior. 4-(Methyloxy)phenyloxy side groups were believed to degrade in the lower temperature range. In DSC and wide-angle X-ray diffractometry APIs all appeared completely amorphous and in UV-Vis spectroscopy both DPAI and APIs were transparent at wavelengths longer than 375 nm.